This has been a solved problem for years in some frameworks, e.g. all the major image upload handling libraries in Rails have this built in an it's very easy to use. There are also plenty of webpack plugins for static assets:

https://github.com/metalabdesign/sharp-loader

https://github.com/herrstucki/responsive-loader

https://github.com/tcoopman/image-webpack-loader

(and many more, just grabbing a few examples)